Ignell et al. SpringerPlus (2016) 5:318 DOI 10.1186/s40064-016-1953-7
Open Access
RESEARCH
Model for individual prediction of diabetes up to 5 years after gestational diabetes mellitus Claes Ignell1,2*, Magnus Ekelund1,3, Eva Anderberg4 and Kerstin Berntorp1,5 *Correspondence: Claes. [email protected] 2 Department of Obstetrics and Gynecology, Helsingborg Hospital, SE‑251 87 Helsingborg, Sweden Full list of author information is available at the end of the article
Abstract Aims: To identify predictors of diabetes development up to 5 years after gestational diabetes mellitus (GDM) and to develop a prediction model for individual use. Methods: Five years after GDM, a 75-g oral glucose tolerance test (OGTT) was performed in 362 women, excluding women already diagnosed with diabetes at 1- to 2-year follow-up or later (n = 45). All but 21 women had results from follow-up at 1–2 years, while 84 women were lost from that point. Predictive variables were identified by logistic regression analysis. Results: Five years after GDM, 28/362 women (8 %) were diagnosed with diabetes whereas 187/362 (52 %) had normal glucose tolerance (NGT). Of the latter, 139/187 (74 %) also had NGT at 1- to 2-year follow-up. In simple regression analysis, using NGT at 1–2 years and at 5 years as the reference, diabetes at 1- to 2-year follow-up or later was clearly associated with easily assessable clinical variables, such as BMI at 1- to 2-year follow-up, 2-h OGTT glucose concentration during pregnancy, and non-European origin (P 3). Diagnosis in early gestation (yes/no) and insulin treatment during pregnancy (yes/no) were also analyzed, but
Study groups Included at 1- to 2-year follow-up
GNGT 166
Diabetes at 1-2 years Not reachable/moved
0 5
Invited to 5-year follow-up Diabetes after 1-2 years Declined Dropped out No results at 1-2 years Included at 5-year follow-up Normal glucose tolerance Impaired fasting glucose Impaired glucose tolerance Diabetes
GDM 470 32 7
161
431 0 22 12
4
13 48 29 21
131 99 (76) 28 (21) 4 (3) 0
362 187 (52) 75 (21) 72 (20) 28 (8)
Fig. 1 Flow chart of the study population and diagnoses at 5-year follow-up. Number of participants and n (%) for diagnosis at 5-year follow-up are given. GNGT gestational normal glucose tolerance, GDM gestational diabetes mellitus
Ignell et al. SpringerPlus (2016) 5:318
they were not included in the final multiple model since these variables were deemed less stable depending on the screening strategy and the judgement by the physician. Multivariable logistic regression analysis was done with either backward elimination of non-significant factors or forward adding of significant factors. Probability of diabetes (%) in the prediction model was calculated from the function: F(t) = et/(1 + et), where t is represented by the equation from the final multivariable regression (Hosmer and Lemeshow 2005). The performance of the prediction model was assessed in receiveroperating characteristic (ROC) curves with calculations of area under the curve (AUC). Threshold for discrimination was calculated with the Youden index (Hajian-Tilaki 2013). IBM SPSS Statistics 22 for Windows (IBM Corporation, Armonk, NY) was used for analysis. Two-sided P values of less than 0.05 were considered to be statistically significant.
Results Altogether, 131 women with GNGT and 362 women with GDM had an OGTT 5 years postpartum (Fig. 1). Frequencies of overweight (BMI ≥ 25 kg/m2) in these groups were 42 and 44 %, respectively, at the 1- to 2-year follow-up (P = 0.50), and 47 % in both groups at the 5-year follow-up. None of the women with GNGT were diagnosed with diabetes at the 1- to 2-year follow-up or later, whereas in addition to the 45 women already diagnosed with diabetes, 28 other women with previous GDM were diagnosed with diabetes at the 5-year appointment. Of the 72 women with IGT 5 years after GDM, 32 (44 %) also had impaired fasting glucose (IFG). Of the 362 women with previous GDM, 341 also had results from the 1- to 2-year follow-up. Adding the 45 women already diagnosed with diabetes at 1- to 2-years or later, altogether 72/386 (19 %) of the women had a diabetes diagnosis 5 years after GDM. In women with IFG or IGT at the 1- to 2-year OGTT, 18/117 (15 %) had diabetes at the 5-year OGTT. The corresponding figure in women with NGT at the 1- to 2-year OGTT was 9/224 (4 %). Using NGT as a reference, IFG or IGT at 1- to 2-year follow-up was associated with an increased risk of diabetes up to 5 years postpartum (OR 5.1, 95 % CI 2.5–10.4, P
Open Access
RESEARCH
Model for individual prediction of diabetes up to 5 years after gestational diabetes mellitus Claes Ignell1,2*, Magnus Ekelund1,3, Eva Anderberg4 and Kerstin Berntorp1,5 *Correspondence: Claes. [email protected] 2 Department of Obstetrics and Gynecology, Helsingborg Hospital, SE‑251 87 Helsingborg, Sweden Full list of author information is available at the end of the article
Abstract Aims: To identify predictors of diabetes development up to 5 years after gestational diabetes mellitus (GDM) and to develop a prediction model for individual use. Methods: Five years after GDM, a 75-g oral glucose tolerance test (OGTT) was performed in 362 women, excluding women already diagnosed with diabetes at 1- to 2-year follow-up or later (n = 45). All but 21 women had results from follow-up at 1–2 years, while 84 women were lost from that point. Predictive variables were identified by logistic regression analysis. Results: Five years after GDM, 28/362 women (8 %) were diagnosed with diabetes whereas 187/362 (52 %) had normal glucose tolerance (NGT). Of the latter, 139/187 (74 %) also had NGT at 1- to 2-year follow-up. In simple regression analysis, using NGT at 1–2 years and at 5 years as the reference, diabetes at 1- to 2-year follow-up or later was clearly associated with easily assessable clinical variables, such as BMI at 1- to 2-year follow-up, 2-h OGTT glucose concentration during pregnancy, and non-European origin (P 3). Diagnosis in early gestation (yes/no) and insulin treatment during pregnancy (yes/no) were also analyzed, but
Study groups Included at 1- to 2-year follow-up
GNGT 166
Diabetes at 1-2 years Not reachable/moved
0 5
Invited to 5-year follow-up Diabetes after 1-2 years Declined Dropped out No results at 1-2 years Included at 5-year follow-up Normal glucose tolerance Impaired fasting glucose Impaired glucose tolerance Diabetes
GDM 470 32 7
161
431 0 22 12
4
13 48 29 21
131 99 (76) 28 (21) 4 (3) 0
362 187 (52) 75 (21) 72 (20) 28 (8)
Fig. 1 Flow chart of the study population and diagnoses at 5-year follow-up. Number of participants and n (%) for diagnosis at 5-year follow-up are given. GNGT gestational normal glucose tolerance, GDM gestational diabetes mellitus
Ignell et al. SpringerPlus (2016) 5:318
they were not included in the final multiple model since these variables were deemed less stable depending on the screening strategy and the judgement by the physician. Multivariable logistic regression analysis was done with either backward elimination of non-significant factors or forward adding of significant factors. Probability of diabetes (%) in the prediction model was calculated from the function: F(t) = et/(1 + et), where t is represented by the equation from the final multivariable regression (Hosmer and Lemeshow 2005). The performance of the prediction model was assessed in receiveroperating characteristic (ROC) curves with calculations of area under the curve (AUC). Threshold for discrimination was calculated with the Youden index (Hajian-Tilaki 2013). IBM SPSS Statistics 22 for Windows (IBM Corporation, Armonk, NY) was used for analysis. Two-sided P values of less than 0.05 were considered to be statistically significant.
Results Altogether, 131 women with GNGT and 362 women with GDM had an OGTT 5 years postpartum (Fig. 1). Frequencies of overweight (BMI ≥ 25 kg/m2) in these groups were 42 and 44 %, respectively, at the 1- to 2-year follow-up (P = 0.50), and 47 % in both groups at the 5-year follow-up. None of the women with GNGT were diagnosed with diabetes at the 1- to 2-year follow-up or later, whereas in addition to the 45 women already diagnosed with diabetes, 28 other women with previous GDM were diagnosed with diabetes at the 5-year appointment. Of the 72 women with IGT 5 years after GDM, 32 (44 %) also had impaired fasting glucose (IFG). Of the 362 women with previous GDM, 341 also had results from the 1- to 2-year follow-up. Adding the 45 women already diagnosed with diabetes at 1- to 2-years or later, altogether 72/386 (19 %) of the women had a diabetes diagnosis 5 years after GDM. In women with IFG or IGT at the 1- to 2-year OGTT, 18/117 (15 %) had diabetes at the 5-year OGTT. The corresponding figure in women with NGT at the 1- to 2-year OGTT was 9/224 (4 %). Using NGT as a reference, IFG or IGT at 1- to 2-year follow-up was associated with an increased risk of diabetes up to 5 years postpartum (OR 5.1, 95 % CI 2.5–10.4, P
